It is known in the art to construct structural units, such as beams, columns, slabs, and the like from modular units fastened together into arrays
However, arrays disclosed in the art outside of the disclosure of U.S. Ser. No. 828,312 require for their construction the grinding of contact surfaces of the individual modular units to a high degree of smoothness as in U.S. Pat. No. 2,102,447 to D. D. Whiteacre in order to eliminate cracking of the individual units from uneven distribution of load on the surface of the units when said units are formed from cementitious substances or the like. The specific embodiments of the present invention utilize the principle described initially described in Ser. No. 828,312 of the use of integrally attached load-bearing surfaces to remove the necessity of grinding the aforesaid contact surfaces as described in U.S. Pat. 2,102,447 to D. D. Whiteacre.
It is also known in the art to fasten individual modular units together via bolts passing thru and attaching adjacent modular units to one another thus forming an array as in U.S. Pat. 3,295,286 issued to W. A. Schaich. However, the present invention presents an improvement which utilizes the same principle originally disclosed in U.S. Ser. No. 828,312 to remove the necessity of positioning each modular unit over the extended fixed bolts used to attach the aforesaid unit to the array as disclosed in U.S. Ser. No. 3,295,286. The aforesaid method disclosed in Ser. No. 828,312 consists of attachment of individual structural units to the array through the insertion of rods back through the modular unit placed in abutment with a modular unit previously made to form part of an array and subsequent attachment of the rods to a modular unit previously made to form part of the array so that the load-bearing surfaces of the modular unit to be attached to the array are placed in compressive contact with the loadbearing surfaces of a modular unit previously attached to the array.
The present invention also allows for increased strength in structural arrays from modular units through a specific system of attachment of individual modular units herein described such that stressing is accomplished through three modular units wherein the middle modular unit is held in compression by the adjacent two units as originally disclosed in U.S. Ser. No. 828,312 such that stressing through three adjacent modular units is in a recurring, interlocking pattern.